华南地质2023，Vol.39Issue(4)：617-629,13.DOI:10.3969/j.issn.2097-0013.2023.04.003
桂西大化辉绿岩岩石成因及对区域构造演化的指示
Petro-genesis of Dahua Diabase in Western Guangxi and Its Indications for Regional Tectonic Evo-lution
摘要
Abstract
There is a large number of layered and quasi-layered dolerite in the Dahua area of western Guangxi,and their petrogenesis is of great significance to the understanding of the regional tectonic evolution processes and the characteristics of the mantle source.In this paper,geochemical and Sr-Nd isotopic studies of Dahua dolerite show that the Dahua dolerite belongs to the alkaline basalt series,with high TiO2 content(2.00～3.82 wt.%)and Ti/Y ratios(860～1176)and generally has the content and characteristics of rare earth el-ement and trace elements similar to those of the high-Ti/Y Emeishan basaltic serie,which may represent the eastward extension of the magmatism of the Emeishan mantle plume.However,compared with the Emeishan high Ti/Y basalts,the Dahua dolerite shows obvious depletion of high field strength elements Nb,Ta,Zr and Hf,and exhibits relatively high 87Sr/86Sr(t)values(0.710087～0.712849)and moderately lower εNd(t)values(-1.68～1.21)The data combined shows that the primary magmas of the Dahua dolerite have possibly originat-ed from the material of Emeishan mantle plume,and the magma have subsequently mixed with the enriched lithospheric mantle material underlying the Yangtze block during its ascent.The Dahua dolerite is located in the middle of the Youjiang basin,far away from Ailaoshan-Majiang Suture Zone,and the Dahua dolerite and its surrounding areas do not reveal earlier or simultaneous subduction-related magmatic rocks.Therefore,the enriched lithospheric mantle involved in the Dahua dolerite may be formed by the modification of earlier tec-tono-thermal events.关键词
峨眉山地幔柱/辉绿岩/岩石成因/岩石圈地幔/构造演化/桂西Key words
Emeishan mantle plume/dolerite/petrogenesis/lithospheric mantle/western Guangxi分类
地质学引用本文复制引用
石钰祥,刘希军,李政林,刘潇,赵兵,覃显著,张一尘,黄雯敏,苏悦..桂西大化辉绿岩岩石成因及对区域构造演化的指示[J].华南地质,2023,39(4):617-629,13.基金项目
广西战略性关键矿产资源成矿与勘查科技创新基地建设项目(桂科ZY21195031)、广西八桂学者项目(有色金属成矿理论与勘查技术)、广西中青年教师基础能力提升项目(2023KY0270)、广西自然科学基金-青年基金(2022GXNSFBA035538) （桂科ZY21195031）
